Intraoral perineurioma: report of a case with a review of the literature

Soft tissue perineurioma of the tongue: report of a case and review of the literature

Perineurioma is a rare benign tumor of the peripheral nervous system distinct from schwannomas and neurofibromas. It may be intraneural or extraneural (in the soft tissue). Extraneural soft tissue perineuriomas are uncommon; rare cases have been reported in the oral cavity. We present a case of soft tissue perineurioma in the tip of the tongue. The tumor was characterized by slender spindle cells, arranged in short fascicles or whorls, and focal areas showing a distinct storiform pattern. Tumor cells showed the immunohistochemical profile of perineurial cells, including epithelial membrane antigen. Smooth muscle actin, S-100, and CD34 were not expressed by the tumor cells. The tumor was surgically excised and in 2 years there has been no recurrence. Knowledge of the tumor in the oral cavity is important to reach a correct diagnosis and to avoid unnecessary aggressive local excision.

Schwannoma causing resorption of zygomatic arch

Schwannoma (also known as neurilemmoma, peripheral glioma and peripheral nerve sheath tumor) is a common, histologically distinctive, benign, usually encapsulated, peripheral nerve tumor of Schwann cell origin. Schwannomas can appear anywhere in the body, but are more frequently reported in the head and neck with an incidence of 25-48% in maxillofacial region. Resorption of bones due to schwannoma is rarely noticed in maxillofacial region. We hereby present a case report of schwannoma in a 35-year-old female, causing resorption of zygomatic arch along with review of literature.

Intraoral perineurioma, soft tissue type: report of five cases, including 3 intraosseous examples, and review of the literature

Soft tissue type perineuriomas (STP) are uncommon tumors, oral examples being very rare. They have been described in the mandible, gingiva, lips, retrotonsillar mucosa and maxillary vestibule. Herein, we report the clinicopathologic features of five STP, two affecting the buccal mucosa and three the mandible. Three patients were women and two men. All tumors were characterized by a proliferation of cytologically bland, mitotically inactive spindled cells with round, ovoid or spindled nuclei, embedded in a variably collagenous and myxoid matrix. Interestingly, two mandibular tumors featured psammoma bodies and one, in addition, contained irregular calcifications. Tumor cells showed the immunohistochemical profile of perineurial cells including epithelial membrane antigen, Glut-1, claudin-1 and collagen type IV. S100 and neurofilament proteins were not expressed by the tumor cells. A few minute, peripherally situated, entrapped nerves were identified. All tumors were reported gross-totally excised and no recurrences have taken place. The clinical characteristics of STP are summarized and its differential diagnosis relative to other spindle cells tumors and meningioma is discussed.

Extraneural sclerosing perineurioma of the buccal mucosa: a case report and clinicopathologic review

The perineurioma is an infrequently encountered benign peripheral nerve sheath tumor composed of a clonal proliferation of perineurial cells. Rare cases of perineurioma have been reported in the oral cavity. An extraneural sclerosing perineurioma arising in the buccal mucosa of a 17-year-old male is presented. Histopathologically, the tumor is composed of a well circumscribed nodular proliferation of spindle cells arranged in a storiform growth pattern, in some areas subtly arranged around vascular channels. The tumor cells reveal positive immunostaining for epithelial membrane antigen (EMA), collagen type IV and vimentin, and negative immunostaining for S-100 protein, consistent with a perineurial origin. To the best of our knowledge, this case represents the first report of an extraneural sclerosing perineurioma involving the oral cavity.

Intraneural perineurioma: a systematic review with illustrative cases

CONTEXT

Intraneural perineurioma may be confused with other "onion bulb" Schwann cell entities (localized hypertrophic neuropathy, reactive/demyelinating processes, or inherited polyneuropathies of Charcot-Marie-Tooth/Dejerine Sottas) due to similar clinical, radiologic, and histologic features. Perineurial and Schwann cells can only be differentiated by ultrastructure and immunohistochemsitry.

OBJECTIVE

To identify and summarize the clinicopathologic features of true cases of intraneural perineurioma from the English language literature.

DATA SOURCES

A systematic review was performed on definitive intraneural perineuriomas identified through Medline. Baylor College of Medicine-affiliated hospitals' anatomic pathology databases yielded 2 illustrative intraneural perineurioma cases.

STUDY SELECTION

Intraneural perineurioma inclusion criteria consisted of characteristic histology and confirmation of perineurial cell lineage by either immunohistochemistry (epithelial membrane antigen positive, S100 protein negative) and/or ultrastructural analysis (thin cytoplasmic processes with an incomplete basal lamina, poorly formed tight junctions, and pinocytotic vesicles).

DATA EXTRACTION

Clinicopathologic data were extracted from all identified articles, with subsequent statistical analysis of the following parameters: age, sex, race, tumor location, tumor size, duration of symptoms prior to diagnosis, treatment modalities and outcomes measures, follow-up assessment for tumor recurrence and metastasis, clinical features (history of trauma, motor/sensory abnormalities, clinical/family history), and diagnostic workup (routine histology, immunohistochemistry, ultrastructural analysis, and molecular/cytogenetic characteristics).

CONCLUSIONS

Intraneural perineurioma is a neoplastic proliferation of perineurial cells with unique immunohistochemistry and ultrastructural features, and it is distinct from other onion bulb Schwann cell-derived entities. Despite harboring molecular abnormalities of the long arm of chromosome 22, intraneural perineurioma has not been associated with neurofibromatosis. Intraneural perineurioma is a benign peripheral nerve sheath tumor that does not recur or metastasize.

Intraneural perineurioma of the oral mucosa

A 16-year-old boy presented with an intraneural perineurioma arising from a small nerve in the buccal mucosa. Histologically, the tumour comprised a tortuous proliferation of spindle cells arranged like an onion bulb. To our knowledge this is the third example of an intraneural perineurioma that did not present in a major nerve.

Schwannoma with secondary erosion of mandible: case report with a review of the literature

Schwannoma (neurilemmoma) is a common, histologically distinctive, benign, usually encapsulated, peripheral nerve tumour of Schwann cell origin. We report a case of schwannoma arising from soft tissue near the mandible. A 53-year-old female presented at our department with painless swelling of lingual mucosa of the mandible. The first molar was extracted 20 months before. Panoramic radiograph showed a suspected residual cyst. It was impossible to determine prior to surgery whether this was a peripheral nerve sheath tumour. The lesion was completely removed; the tumour appears to have originated in soft tissue and caused secondary erosion of the mandible.

Comparative ultrastructural and immunohistochemical study of perineurioma and neurofibroma of the oral mucosa

In the course of assessing the cellular composition of intraoral neurofibroma (NF), we encountered a unique gingival tumor of putative perineurial (PN) origin. The lesion showed the ordinary light microscopic NF pattern, but the ultrastructural features of well-differentiated PN cells as well as an epithelial membrane antigen (EMA)-positive, S-100 protein-negative immunoprofile confirmed the diagnosis of soft tissue perineurioma (STP). In our small series of NF, there were three ultrastructural subtypes: Type I (common Schwann cell type), Type II (NF with a high content of PN cells) and Type III (predominantly fibroblastic NF), although inhomogeneous and overlapping assembly of cellular elements. A significant number of tumor cells in Type II showed the substantial reactivity for EMA, whereas many CD34-positive cells were noted in Type III. The present results confirm previous findings that PN lineage is an important constituent in the formation of NF and reinforce the value of electron microscopy in the diagnosis of peripheral nerve sheath tumors.